<!DOCTYPE html>
<html>
<head>
    <title>Touch article sample 1</title>
</head>
<body>
    <canvas id="drawSurface" width="400px" height="400px" style="border: 1px dashed black;">
    </canvas>
    <script>
        var canvas = document.getElementById("drawSurface");
        var context = canvas.getContext("2d");
        context.fillStyle = "rgba(0, 0, 255, 0.5)";

        canvas.addEventListener("", paint, false);

        function paint(event) {
            context.fillRect(event.clientX, event.clientY, 10, 10);
        }
    </script>
</body>
</html>